There are generally known mobile phones and smartphones (mobile devices) which are each equipped with an electronic purse function, store data of an electronic purse, and make an electronic payment using proximity contactless communication (hereinafter referred to as contactless communication) such as NFC (Near Field Communication) with an automatic ticket gate, for example, as a payment terminal (refer to Japanese Patent Application Laid-Open Publication No. 2001-273528, for example).
In the technique disclosed in Japanese Patent Application Laid-Open Publication No. 2001-273528, a user of a mobile phone performs contactless communication between the mobile phone and an automatic ticket gate when going out of a station through the automatic ticket gate, so that an electronic payment is made via the automatic ticket gate. At the payment, an amount for a fare is withdrawn from the data of an electronic purse stored in the mobile phone.
Recently, smartphones have been rapidly diffused as replacements of mobile phones, and accordingly, electronic payments are often made by contactless communication using the electronic purse function of the smartphones.
Further, with the recent popularization of the smartphones, attention is being focused on an information device in the shape of a watch (hereinafter referred to as a wrist information device) which operates in cooperation with a smartphone.